The invention relates to an arrangement for fixing the position of a coil carrier in a cup-shaped formed casing part. The invention finds particular application in a magnetic sensor.
In the prior art magnetic sensor described in European Patent 0 384 014 B1 (U.S. Pat. No. 5,341,117), the coil carrier is housed in a cup-shaped formed casing part. The cup-shaped formed casing part is closed on one end, which is called the base, and fitted with a closure part on the other. Tongue-like elements are formed on the closure part, and these elements extend in the direction of the coil carrier. Each tongue-like element is provided with a triangular barb that has a shallow face and a steep face. The steep face extends at substantially right angles to the surface is of the coil carrier. The surface of the coil carrier is provided with asymmetrical ridges or grooves forming teeth that interact with the barbs in the manner of a locking connection. That is, the shallow faces of the barbs readily ride over the teeth as the closure part is forced onto the coil carrier. However, the steep faces of the barbs do not ride over the teeth in the opposite direction, thus preventing the closure part and coil carrier from separating.
The coil carrier and the closure part of the prior art arrangement are inserted as a subassembly into the cup-shaped formed casing part until the coil carrier is brought to bear upon the base of the cup-shaped formed casing part. Each tongue-like element is also provided with a rounded projection extending towards the wall of the cup-shaped formed casing part. The rounded projections of the tongue-like elements press against the wall of the cup-shaped formed casing part, so that the coil carrier is centered in the cup-shaped formed casing part.
The performance of the magnetic sensor degrades if the coil carrier does not remain accurately centered and fully inserted in the cup-shaped formed casing part. It is therefore an object of the present invention to improve on the prior art arrangement by providing a simple elastic mounting that absorbs the forces and vibrations exerted on the coil carrier of a magnetic sensor in normal use.